Strontium compounds are used in oxygen-ionic and electronic conductive thin films when being in the form of SrTiO3, SrBi2Ta2O9, BaxSr1-xTiO3, LaSrCoFe, and are found in thin film electroluminescent displays when being in the form of SrGa2S4:Ce. Like this, strontium compounds are used as precursors for preparing strontium-containing heterogeneous metal thin films, nano-size strontium oxides, and strontium-containing heterogeneous metal particles.
In addition, strontium titanate (SrTiO3) and barium strontium titanate ((Ba, Sr)TiO3), both being alkaline earth metal-containing oxides with a Perovskite structure, find applications in various fields including nonvolatile ferroelectric memory, microwave devices, dynamic random access memory (DRAMs), multilayer capacitors, electro optical devices, actuators, transducers, high-k dielectrics, and micro-electromechanical systems (MEMs) (Zhao, J.; Wang, X.; Chen, R.; Li. L. Materials Letters 2005, 59, 2329; Mao, Y.; Baneriee, S.; Wong, S. S. J. Am. Chem. Soc. 2003, 125, 15718; Gong, D.; Grimes, C. A.; Varghese, O. K; Hu, W.; Singh, R. S.; Chen, Z.; Dickey, D. J. J. Mater. Res. 2001, 16, 3331; Padture, N. P. Wei, X. Z. J. Am. Ceram. Soc. 2003, 86, 2215; Phule, P. P.; Risbud, S. H. J. Mater. Sci. 1990, 25, 1169; Hill, N. A. J. Phys. Chem. B 2000, 104, 6694). Further, SrO is known to act as a buffer layer between Si and SrTiO3, and alkaline earth thiogallates such as SrGa2S4:Ce are studied for use in phosphor thin films of electroluminescent displays (Asaoka, H.; Saiki, K.; Koma, A.; Yamamoto, H. Thin Solid Films 2000, 369, 273; Okamoto, S.; Tanaka, K.; Inoue, Y. Appl. Phys. Lett. 2000, 76, 946; Tanaka, K.; Inoue, Y.; Okamoto, S.; Kobayashi, K. J. Cryst. Growth 1995, 150, 1211).
To prepare the above-mentioned materials, various methods such as sol-gel, MOD (metal-organic decomposition), PLD (pulsed laser ablation), CVD (chemical vapor deposition), MOCVD (metal-organic chemical vapor deposition), ALD (atomic layer deposition), etc. have been employed. For use in these methods, various precursors are known, including alkoxides, aryloxides, b-diketonates, metallocenes, bis(trimethylsilyl)amide, and alkylamide. However, most of these precursors are dimers or higher oligomers with high volatile temperatures. In order to improve their volatility, the precursors are fluorinated, which leads contamination of the thin films with fluorides (Paw, W.; Baum, T. H.; Lam, K.-C.; Rheingold, A. L. Inorg. Chem. 2000, 39, 2011; Mizushima, Y.; Hirabayashi, I. J. Mater. Res. 1996, 11, 2698; Shamlian, S. H.; Hitchman, M. L.; Cook, S. L.; Richards. B. C. J. Mater Chem. 1994, 4, 81; Gardiner, R. A.; Brown, D. W.; Kirlin, P. S.; Rheingold, A. L. Chem. mater. 1991, 3, 1053). Meanwhile, Korean Patent Application Unexamined Publication No. 2008-0113053 discloses a strontium precursor containing a ligand composed only of cyclopentadienyl, but this precursor cannot be a solution to the problems mentioned above.